The present application relates to a communication method and a Bluetooth device utilizing the communication method, and particularly relates to a communication method that can maximize the use efficiency of Bluetooth slots in the scatternet, and a Bluetooth device utilizing the communication method.
FIG. 1 is a schematic diagram illustrating a related art Bluetooth devices in a scatternet. In FIG. 1, the headset 101, the mobile phone 103 and the mobile phone 105 all include a Bluetooth device therein. Accordingly, the mobile phone 103 can transmit data to the headset 101 or receive data from the headset 101 via the Bluetooth devices therein. Such communication relation is named a piconet (herein after piconet A and phone 103 is the master). Simultaneously, the mobile phone 103 and 105 can utilize Bluetooth devices therein to communicate with each other. Such communication relation is also named a piconet (herein after piconet B and phone 103 is the slave). Therefore, phone 103 has a scatternet (Master of the piconet A and slave of the piconet B).
FIGS. 2 and 3 are schematic diagrams illustrating the switching operations between two piconets in the scatternet. According to the specification of Bluetooth, the piconet clock is aligned to the master native clock. So, a device in a scatternet cannot service two piconets at the same time. Each transmission period for each piconet includes a predetermined data capacity (ex. 80 slots), depending on the chip design. In FIG. 2, all the slots in the piconet A are utilized to transmit data (such as the marked D1, D2) and null packets (such as the marked N1, N2). When amount of the data to be transmitted for the piconet A is larger than the data capacity of the transmission period for the piconet A, it needs to wait for 80 slots until the operations are switched back to piconet A, which may cause quality degradation. FIG. 3 is a schematic diagram illustrating that only parts of the slots in the piconet A are utilized. That is, no data of the piconet A needs to be transmitted or all the data needs to be transmitted for the piconet A are already transmitted. In this case, the empty slots may be filled with null packets such as NA, NB from the slave device and poll packets such as PA, PB from the master device, as shown in FIG. 3, or without any traffic, as shown in FIG. 4. However, such mechanism may cause unnecessary data transmission or waste the air bandwidth since the slots are not sufficiently utilized.